Lectures

Question 1

Examples of disorders affecting brainstem

Answer 1

Tumours
Inflammatory disorders e.g. MS
Metabolic e.g. central pontine myelonecrosis (Na+)
Trauma
Spontaneous aneurysm e.g. AVM, aneurysm
Infarction e.g. vertebral artery dissection
Infection e.g. cerebellar abscess from ear

Question 2

Criteria from brainstem death

Answer 2

Pupils
Corneal reflex
Caloric vestibular reflex
Cough reflex
Gag reflex
Respirations
Response to pain

Question 3

Different types of sensory fibres (large and small)

Answer 3

Aα and Aβ (large myelinated fibres)

Aδ and C (thin, small fibres)

Question 4

Difference between Aα and Aβ (large myelinated) sensory fibres

Answer 4

Αα are transmitting signals regarding proprioception and Aβ about light touch, pressure and vibration.

Question 5

Difference and similarity between Aδ and C fibers small, thin sensory fibres

Answer 5

Aδ are myelinated and C unmyelinated
Both transmit signals regarding pain
Additionally, Aδ signals are about cold sensation and C signals are about warm sensation.

Question 6

What is result of demyelinating neuropathies

Answer 6

Myelin is destroyed

Leads to slower conduction velocities

Question 7

What is difference between mononeuropathy and polyneuropathy

Answer 7

Mononeuropathy = problem with one nerve
Polyneuropathy = problem with multiple nerves

Question 8

Examples of common mononeuropathies

Answer 8

Carpal tunnel syndrome
Ulnar neuropathy
Peroneal neuropathy
Cranial mononeuropathies e.g. III or VII cranial nerve palsy

Question 9

What nerve is compressed in carpal tunnel syndrome

Answer 9

Median nerve

Question 10

Cause of ulnar neuropathy

Answer 10

Entrapment at the cubital tunnel

Question 11

Cause of peroneal neuropathy

Answer 11

Entrapment at the fibular head

Question 12

Cause of cranial neuropathies such as III or VII cranial nerve palsy

Answer 12

Idiopathic
Immune mediated
Ischaemic

Question 13

Subtypes of large fibre neuropathies

Answer 13

Axonal

Demyelinating

Question 14

Define peripheral neuropathy

Answer 14

Any disorder of the peripheral nervous system

Can be acute or chronic

Question 15

Types of causes of chronic demyelinating neuropathies

Answer 15

Genetic

Inflammatory

Question 16

What is CIDP

Answer 16

Chronic inflammatory demyelinating polyneuropathy (CIDP)
A rare neurological disorder in which there is inflammation of nerve roots and peripheral nerves and destruction of the fatty protective covering (myelin sheath) over the nerves

Question 17

What is ataxia

Answer 17

Poor balance

Question 18

Causes of ataxia

Answer 18

Sensory - loss of proprioception
OR
Cerebellar

Question 19

In sensory ataxia, what makes it worse

Answer 19

Eyes closed or when dark

Question 20

Motor symptoms of peripheral neuropathies

Answer 20

Muscle cramps
Weakness
Fasciculations - muscle twitches
Atrophy
High arched feet (pes cavus)

Question 21

3 categories of axonal peripheral neuropathies

Answer 21

Symmetrical sensorimotor (or sensory neuropathies)
Sensory gangliopathies (or asymmetrical sensory)
Asymmetrical sensorimotor neuropathies (or mononeuritis multiplex)

Question 22

What is the most common type of peripheral neuropathy

Answer 22

Symmetrical sensori-motor PNs

Question 23

Presentation of symmetrical sensori-motor peripheral neuropathies

Answer 23

Initially sensory symptoms affecting the toes and fingers (Length-dependent pattern) and eventually motor symptoms again in a length dependent pattern.
Long fibres are affected first

Question 24

Example of asymmetrical sensory neuropathy

Answer 24

Sensory gangliopathy

Question 25

In sensory gangliopathy, what structure is affected

Answer 25

Dorsal root ganglia

Question 26

Characteristics of Sensory gangliopathy (asymmetrical sensory PN)

Answer 26

Purely sensory and characteristically presents with patch distribution of symptoms. Dorsal root ganglia are affected. Relatively uncommon overall, but common as a paraneoplastic manifestation or in the context of Sjogren's disease and gluten sensitivity

Question 27

What is Sjogren's disease

Answer 27

A condition that mainly affects the glands that produce saliva and tears, causing a dry mouth and/or eyes

Question 28

Example of asymmetrical sensorimotor PN

Answer 28

Mononeuritis multiplex | Occurs in the context of vasculitis

Question 29

Characteristics of asymmetrical sensorimotor PN

Answer 29

Multiple nerve involvement Can randomly affect any nerve without a specific pattern Very common but painful and occurs in the context of Vasculitis

Question 30

Diagnostic approach to PN (first steps)

Answer 30

History Clinical examination Neurophysiological examination i.e. NCS/QST

Question 31

Diagnostic approach to PN: Clinical examinations done

Answer 31

Reduced or absent tendon reflexes Sensory deficit Weakness - muscle atrophies

Question 32

Diagnostic approach to PN: Neurophysiological examinations

Answer 32

Nerve conduction studies - determine type of neuropathy

Question 33

How would you diagnose a demyelinating PN in nerve conduction study

Answer 33

Reduced conduction velocities and/or conduction block in sensory and motor nerves with minimal or no abnormalities in the SNAP and CMAPs

Question 34

How would you diagnose mononeuritis multiplex PN in nerve conduction study

Answer 34

SNAPs and CMAPs of affected nerves are reduced | Asymmetrical

Question 35

How would you diagnose SMA (Spinal Muscular Atrophy) PN in nerve conduction study

Answer 35

Symmetrical type of sensorimotor pn | Reduced SNAPs in beginning and eventually CMAPs

Question 36

Nerve conduction study: difference between demyelinating and axonal

Answer 36

``` Demyelinating = slow conduction velocities Axonal = reduced amplitudes of the potentials ```

Question 37

Causes of axonal PN

Answer 37

Associated with systemic diseases Inflammatory – immune mediated (mainly acute) Infectious (i.e. hepatitis, HIV, Lyme) Ischemic (i.e. vasculitis) Metabolic (i.e. Fabry’s, porphyria) Hereditary (CMT, HLPP) Toxins (pharmaceuticals, environmental toxins, B6)

Question 38

Systemic diseases associated with axonal PN

Answer 38

``` Diabetes Vitamin deficiency (commonly B12) Gluten sensitivity / coeliac disease Chronic renal disease Excessive alcohol drinking Hypothyroidism Amyloidosis Connective tissue disease Paraproteinemia Paraneoplastic Critical illness polyneuropathy ```

Question 39

What is meant by chronic idioapthic axonal polyneuropathy

Answer 39

Develops over at least 6 months (chronic) No aetiology can be identified despite extensive and appropriate investigations (Idiopathic) Axons are affected, most commonly in proportion to their length (Axonal)

Question 40

Examples of immune mediated chronic demyelinating neuropathy

Answer 40

CIDP (chronic inflammatory demyelinating polyneuropathy) | Multifocal motor neuropathy (MMN)

Question 41

Examples of genetic chronic demyelinating neuropathy

Answer 41

Charcot Marie Tooth disease | Hereditary sensory and autonomic neuropathies

Question 42

Example of an acute polyneuropathy

Answer 42

Guillain Barre syndrome

Question 43

What is Guillain Barre syndrome

Answer 43

Autoimmune disorder in which the immune system attacks healthy nerve cells in your peripheral nervous system (PNS). This leads to weakness, numbness, and tingling, and can eventually cause paralysis.

Question 44

Clinical presentation of Guillain Barre syndrome

Answer 44

Progressive ascending limb weakness (usually symmetrical) that peaks at 4 weeks, usually lost reflexes, some paraesthesia ('walking on rubber'). Little to no muscle wasting. Infection (e.g. GI) may precede the disease (campylobacter)

Question 45

What type of neuropathy is Guillain Barre syndrome

Answer 45

Demyelination and axonal degradation -> progressive ascending neuropathy

Question 46

What is Miller Fisher syndrome

Answer 46

Variant of Guillain Barre syndrome that affects cranial nerves of the eye muscles (opthalmoplegia and ataxia)

Question 47

Aetiology of Guillain Barre syndrome

Answer 47

Most have preceding infection, usually of respiratory and GI. Potentially antibodies to infection also attack peripheral nerves. Usually caused by campylobacter jejuni. Can be CMV

Question 48

Pathophysiology of Guillain Barre syndrome

Answer 48

Demyelination and axonal degeneration -> acute, ascending and progressive neuropathy Probably antibodies from the infection succumb to molecular mimicry and attack myelination

Question 49

Diagnosis of Guillain Barre syndrome

Answer 49

``` Clinical. Antibody screen. Nerve conduction studies. CSF: raised protein level with a normal white cell count. Monitor FVC for respiratory involvement ```

Question 50

Treatment of Guillain Barre syndrome

Answer 50

IV immunoglobulin. Plasma exchange possible. Ventilate if necessary.

Question 51

Complications of Guillain Barre syndrome

Answer 51

Life threatening respiratory failure | Lower Motor Neurone lesion (sequelae)

Question 52

Treatment of neuropathy

Answer 52

``` Aim to identify any reversible cause and stop progression if possible Symptomatic treatment: Pain Cramps (Quinine) Balance (physiotherapy/walking aids) ```

Question 53

Treatment of pain symptoms in neuropathy (medical)

Answer 53

Amitryptilline Gabapentin Pregabalin

Question 54

A 72 year old patient with a 15 year history of diabetes complains of burning sensation and tingling in his both feet for 3 years. Over the last 12 months the symptoms have progressed up to the level of the knees. On examination he has reduced tendon reflexes in the upper limbs and the knees and absent tendon reflexes in the ankles. He has reduced vibration sensation up to the knees. What is the most likely diagnosis?

Answer 54

Peripheral neuropathy of axonal type (length dependent) ``` Diabetes Burning sensation and tingling Reduced tendon reflexes Absent tendon reflexes in the ankles Reduced vibration sensation up to the knees ```

Question 55

A 32 year old woman with a 5 day history of progressive weakness and tingling which started from the lower limbs but now has affected the upper limbs too. On examination she has absent tendon reflexes. Her medical history is unremarkable, however she reports D&V about 3 weeks ago. What is the most likely diagnosis?

Answer 55

Acute polyneuropathy Guillain Barre syndrome 5 day started from the lower limbs absent tendon reflexes D and V about 3 weeks ago

Question 56

A 52 year old man reports patchy sensory loss and complains of poor balance, symptoms which are getting gradually worse. Ten year earlier he was diagnosed with coeliac disease. On examination he has mild sensory ataxia, reduced reflexes and patchy loss of pinprick and vibration sensation. What is the most likely diagnosis?

Answer 56

Sensory ganglionopathy Patchy sensory loss Poor balance Coeliac disease